Yes and no. It can be profitable for both as you provide capital upfront that they would have had to wait what ever the contract was to get. This allows faster growth or investment as well as a exact amount of capital for the mining all for the "fee" of the difference between what they raise and what they mine. The investors are taking on the risk of the possibility of not getting the full return however it's possible (and likely if done right) to make a fair profit. But they take on all risk from huge difficulty jumps, legislation making it less profitable, entire company issues such as poor management or hardware failures that they simply can't fix/replace.

All in all yes it's risky and I personally wouldn't invest in it but a reasonable model for the right investor.